Wire bonders are used in semiconductor packaging to form electrical interconnections between separate locations within a semiconductor package. A wire bonder will comprise a bonding device for forming the electrical interconnections within the semiconductor package. Typically, the bonding device includes a transducer for providing bonding energy and a bonding tool through which a bonding wire is introduced to form the electrical interconnections within the semiconductor package.
For example, an ultrasonic transducer of a wire bonder is mechanically driven to move the bonding tool tip in a scrubbing motion during ball bonding to clean a die pad surface of a semiconductor die. The ultrasonic transducer also provides ultrasonic bonding energy during ball bonding to cause adhesion of a ball bond of the bonding wire with the die pad surface. Good adhesion of the ball bond with the die pad surface accordingly reduces the likelihood of the ball bond being detached from the die pad surface when the wire is pulled by the wire bonder from the die pad towards the leadframe to form an electrical interconnection within the semiconductor package.
As the ultrasonic transducer is linearly driven along its longitudinal axis, the scrubbing motion of the bonding tool tip will also be linear with respect to the longitudinal axis of the ultrasonic transducer. Such a linear scrubbing motion of the bonding tool tip may not sufficiently clean the die pad surface, thereby affecting the quality of the ball bonding process. Moreover, as the ultrasonic transducer generally provides bonding energy at a fixed ultrasonic frequency range, this may also compromise the bond strength between the ball bond and the die pad surface of the semiconductor die.
Thus, it is an object of the present invention to seek to address any of these limitations of conventional wire bonders.